Castle push is when the whole Alliance works together to help one member build a castle.
This is a proven way to help the whole Alliance grow stronger faster. It's especially helpful when the castles start getting bigger and needing more resources to upgrade.
In order to be eligible for Castle push, you have to be at least an R2 and have a trade station. Cancel push order will be determined by lifetime donation rankings. If you move up in the rankings, you will also move up in the order.
When the program starts, the eligible player with the highest donation ranking will be the first one to be pushed. That person will tell how many resources they need to push their Castle to the next level. Then all members will donate what they can until that person has enough to upgrade their Castle. The push will then move to the next eligible member, and so on.
Sometimes, someone will leave the alliance for some reason or other. If you rejoin the alliance, you will go to the bottom of the lifetime donation rankings. If you leave the alliance to go hunting on your own, or because you need to attack your farm Castle, take a screenshot of your alliance ranking before you leave. Keep track of where you would be in the rankings if you had not left and let the administrator know when your turn is getting close. If you leave to join another Alliance, and then come back, I'm afraid you'll have to stay at the bottom of the rankings and work back up.